Cuil Inc (pronounced "cool") is offering a new search service at www.cuil.com that the company claims can index, faster and more cheaply, a far larger portion of the Web than Google, which boasts the largest online index.

MENLO PARK, California (Reuters) - A start-up led by former star Google engineers on Sunday unveiled a new Web search service that aims to outdo the Internet search leader in size, but faces an uphill battle changing Web surfing habits.

Cuil Inc (pronounced "cool") is offering a new search service at www.cuil.com that the company claims can index, faster and more cheaply, a far larger portion of the Web than Google, which boasts the largest online index.

The would-be Google rival says its service goes beyond prevailing search techniques that focus on Web links and audience traffic patterns and instead analyzes the context of each page and the concepts behind each user search request.

"Our significant breakthroughs in search technology have enabled us to index much more of the Internet, placing nearly the entire Web at the fingertips of every user," Tom Costello, Cuil co-founder and chief executive, said in a statement.

Danny Sullivan, a Web search analyst and editor-in-chief of Search Engine Land, said Cuil can try to exploit complaints consumers may have with Google -- namely, that it tries to do too much, that its results favor already popular sites, and that it leans heavily on certain authoritative sites such as Wikipedia.

"The time may be right for a challenger," Sullivan says, but adds quickly: "Competing with Google is still a very daunting task, as Microsoft will tell you."

Microsoft Corp, the No. 3 U.S. player in Web search has been seeking in vain, so far, to join forces with No. 2 Yahoo Inc to battle Google.

Cuil was founded by a group of search pioneers, including Costello, who built a prototype of Web Fountain, IBM's Web search analytics tool, and his wife, Anna Patterson, the architect of Google Inc's massive TeraGoogle index of Web pages. Patterson also designed the search system for global corporate document storage company Recall, a unit of Australia's Brambles Ltd

The two are joined by two former Google colleagues, Russell Power and Louis Monier. Previously, Monier led the redesign of ecommerce leader eBay Inc's search engine and was the founding chief technology officer of two 1990s Web milestones, AltaVista and BabelFish, the first language translation site.

"They do have the talent that is used to building large, industrial-strength search engines," Sullivan says of Cuil.

Cuil clusters the results of each Web search performed on the service into groups of related Web pages. It sorts these by categories and offers various organizing features to help identify topics and allow the user to quickly refine searches.

User privacy is another appeal of its approach, Cuil says. Because the service focuses on the content of the pages rather than click history, the company has no need to store users' personal information or their search histories, it says.

"We are all about pattern analysis," Patterson says. "We go over the corpus (Web pages) 12 times before we even index it."